'Freedom is on the line': Biden, Zelenskyy push for Ukraine aid in joint news conference

Ukrainian President Volodymyr Zelenskyy capped off a whirlwind day in Washington on Tuesday with a press conference alongside President Joe Biden, who said Ukraine's "freedom is on the line" as a massive military aid package remains stalled in Congress where Republicans are pushing major changes to border policy.

The two leaders addressed reporters following a meeting in the Oval Office, laying out their vision for Ukraine's future and what role the U.S. should play in helping the Eastern European nation stave off Russia's invasion.

"[Vladimir] Putin is banking on the United States failing to deliver for Ukraine," Biden said. "We must, we must, we must prove him wrong. The United States Congress must act."

Biden also had this message for Zelenskyy: "Mr. President, I will not walk away from Ukraine and neither will the American people."

Zelenskyy thanked the U.S. for its support and said together the two nations can "strengthen democracy's arsenal."

But despite Zelenskyy's visit, it appears Congress is heading into its winter holiday recess without a resolution on the Biden-backed supplemental aid package that includes billions of dollars for Ukraine, Israel and Taiwan as well as border enforcement.

The funding is tied up in a legislative fight as Republicans insist on significant changes to border security and immigration policy, though their exact demands remain publicly unclear.

Senate Minority Leader Mitch McConnell, a staunch supporter of continuing Ukraine aid, wasn't optimistic the impasse would be broken by the time lawmakers leave for holiday recess. McConnell told reporters earlier Tuesday that it was "practically impossible" to get the funding package across the finish line before Christmas even if an agreement is reached soon.

He also said, however, that addressing the border is key.

"When it comes to keeping America safe, border security is not a side show -- it is ground zero," he said.

House Speaker Mike Johnson echoed that, telling reporters, "I've ... made very clear from day one that our first condition on any national security supplemental spending package is about our own national security,"

"The border is an absolute catastrophe," he said.

Republicans are putting pressure on the White House to do more in the negotiations, while Biden on Tuesday accused Republicans of holding critical aid hostage.

"If you're being celebrated by Russian propagandists, it might be time to rethink what you're doing," he said.

Biden said his team is working with Senate Democrats and Republicans to try to find a "bipartisan compromise" on border policy, saying Congress does need to "to fix the broken immigration system here at home."

"Compromise is how democracy works, and I'm ready and offered compromise already," he said. "Holding Ukraine's funding hostage in an attempt to force through an extreme Republican partisan agenda on the border is not how it works."

Asked if he heard what he wanted from lawmakers in his own meetings on Capitol Hill on Tuesday or if he was more concerned than he was before, Zelenskyy said he felt support but had to "separate" words and action.

"I got the signals, they were more than positive," he said. "But we know that we have to separate words and particular result. Therefore we will count on particular result."

Senate Majority Leader Chuck Schumer, D-N.Y., criticized House Republicans for planning to leave town at the end of the week for recess.

"They say it's an emergency at both the border and in Ukraine -- you don't go home for three weeks," Schumer said.

Some Senate Republicans agree they should stay in town until they can strike an agreement.

"Not negotiating, walking away and letting us go for two or three weeks without negotiating in my opinion is irresponsible. We've got to move in real time," North Carolina's Thom Tillis told ABC News Chief White House Correspondent Mary Bruce.

Earlier Tuesday, during his Oval Office meeting with Zelenskyy, Biden announced a $200 million military package under the presidential drawdown authority -- a fund that is running low, which is why the administration is requesting more from Congress.

The two had also planned to discuss how they can strengthen the aid Ukraine is getting, and Ukraine possibly joining the European Union.

“Everything we talked about today will help us in the year 2024," Zelenskyy said afterward. "Today's discussions in the White House and in Congress across both parties and both chambers, with the speaker were very productive. And I thank you for the bipartisan support as we approach Christmas on behalf of all of our Ukrainian families."

ABC News' Mariam Khan, Sarah Kolinovsky and Molly Nagle contributed to this report.